Reviews by patients who have Tooth Pain and take Zinc either as part of daily diet or as method of treatment. Positive and negative experiences from patients with Tooth Pain that take Zinc
1 Red or black colored stool may be a sign of bleeding in the GI tract (from the esophagus, stomach, small intestine or colon) and should not be ignored.  When stool color changes, what tests need to be done depend upon depends upon what cause is suspected for the stool color change.
Black dyes in foods such as licorice or foods colored with black food coloring can cause your stool to turn black. Other than food coloring or dyes, there is no other food-related reason why your stool would turn black. Black stool can indicate a serious condition, such as blood in your stool.